Greg Detre
Saturday, May 17, 2003
at the risk of adding to the canon of extant just-so stories, i am going to try and sketch an argument, resting on a minimum of assumptions, for why the TDC framework should be arise in any thinking thing
where there�s life (process that maintains itself, transduces, reproduces) there�s scarcity
where�s there�s scarcity, there�s death
where there�s death, there�s selection (assuming that there is a source of variation)
where there�s selection, there�s pressure to exploit the world increasingly efficiently
doesn�t there also have to be heritance???
where there�s pressure to exploit the world increasingly efficiently, there will be an arms race � this will lead to increasingly close-fitting and complex models of the world
more complex models require longer and more memory to learn + remember � if you can represent them more compactly and generate all the data you need, then you can have a more complex model without the memory + learning-time costs
compression can be expressed in terms of the MDL � the more structure there is in the world, the more you benefit from really good, abstract, compact, generative models because you can really reduce the number of uninformative noisy exceptions that you need to capture the data
in other words, having good models helps you
benefit, which means that you�re more likely to survive and propagate your genes, which means that those genes are more likely
to proliferate,
can you not think of genes in non-genetic terms, but
more as just something that gets passed to the next generation � could you
think of memes as inherited???
more compact representations allow you to know more about the world � he�s arguing that the most compact representations are things, differences and causes � why though?
the most useful kind of knowledge that you can have is what to do in order to maximise reward
in order to do that, you need to have a sense of
choice, or at least of alternatives �
I think we can see the first 3 levels of the model 6
as being a kind of obvious, obvious track for the intelligent arms race above
once you�ve got as far as level 3, you�ve got the
ability to choose between alternatives
so then you can make use of knowledge to direct your
actions� hmmm � this isn�t going anywhere
so, to backtrack: the most useful kind of knowledge that you can have is what to do in order to maximise reward
there are consequences you like � you need some sort of reward function then, right??? � these are goals???
anyway, causes are those things (or differences???) that are most richly generative of the consequences you like
as soon as you have a means of representing hypotheticals, you can compare between present, past + possible worlds
or to put it another way, as soon as you have a means of comparing� then what??? this doesn�t work � you need to put it the other way as above
as soon as you have a basic, first-order intentionality predictive model of others, it will get more complex
then, as before, you will try and break it into compositions because they�re better for storage (and we know that minds are structured, hence compressible and decomposable)
and what�s better for storage is better for generation
once you start to represent other people as decomposable, then what will you find to be the best way of decomposing them??? beliefs and desires??? their own things, differences + causes??? goals??? consequences??? things, differences and causes about the way they work
the thing is, I�ve justified TDC at some levels, but by no means at all � and indeed, the argument will become increasingly tenuous if I try to � the question is why TDC at every level??? you might be forgiven for thinking that it would be great for certain levels but not for others�
does level 3 (deliberative) have TDC??? of what kind??? see steve�s paper � it definitely has difference � and I suppose each complete hypothetical scenario is a thing � there�s a single cause, which is the best scenario which causes your behaviour � but I don�t think that there are component notions of cause within the different scenarios
scarcity � proved
evolution � proved
composition as following from an intellect arms race � proved
things/differences as the best way to decompose??? � not proved
need for consequences/goals in order to explain the need for causes???
causes as meta-analogies??? � take two pairs of situations (clauses), see the difference between them,
argue that TDC (things, differences, causes) are in some sense operations
argue that the notion of clause is underdetermined, nebulous and redundant
need for consequences/goals???
C&C3 just-so story